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1. Field of the Invention
The present invention generally relates to pressure vessels for refrigeration systems. More specifically, this invention is directed to an apparatus, and a related method of manufacturing, for a receiver-dryer for a vehicle air-conditioning system, wherein the design is optimized to reduce manufacturing costs.
2. Description of the Related Art
In most vehicle air-conditioning systems, it is common to use one or the other of a receiver-dryer or an accumulator for various benefits. A receiver-dryer is typically located at the outlet end of a condenser in the pressure-side section of a refrigeration circuit. The receiver-dryer or accumulator is used for i) removing water from the refrigerant fluid, ii) screening out particulate matter, and iii) acting as a reservoir for the refrigerant fluid when refrigeration system demand is low.
A typical receiver-dryer includes a canister having an inlet port and a centrally positioned outlet port. An inlet tube extends through the inlet port and communicates with an upper interior portion of the canister, while an outlet tube extends through the outlet port and communicates with a lower interior portion of the canister. Desiccant and filter devices of various shapes, sizes, and structures have been fastened within the typical canister to screen and dry refrigerant passing between the inlet tube and outlet tube. Until now, however, such devices have been unnecessarily costly, difficult to assemble, and in some cases inefficient in operation. Therefore, efforts to improve the manufacturability of such devices continue.
For example, U.S. Pat. No. 5,865,998 to Abraham et al. teaches an improved desiccant bag that can be mounted with a receiver-dryer body without the use of any mounting plates. Abraham et al. disclose the receiver-dryer having an outlet tube with a retaining shoulder located thereon. Further, the desiccant bag includes a shell having a disc-shaped filter lid with a mounting hole formed therein and a rigid eyelet surrounding the mounting hole. The desiccant bag mounts over the outlet tube wherein the tube extends through the mounting hole and the rigid eyelet locates against the retaining shoulder to support the eyelet and limit movement of the desiccant bag within the receiver-dryer body. Unfortunately, however, the Abraham et al. desiccant bag is a very specialized design and is not as widely available as existing desiccant bag designs.
Another example is disclosed in U.S. Pat. No. 6,178,772 to Incorvia, which teaches an improved combined filter and absorbent unit for a refrigerant receiver. Incorvia discloses that the filter unit consists of a disc-shaped filter portion extending radially outwardly from one end of an elongated tubular portion, wherein the filter portion either can be staked to the elongated tubular portion or can be integral therewith. The filter portion includes a circumferential seal therearound for sealing with an interior wall of the refrigerant receiver. An adsorbent container includes opposed bag portions and a yoke therebetween that is mounted to the elongated tubular portion such that the elongated tubular portion extends through a central aperture of the yoke. A rim circumscribes or defines the aperture, and is fused circumferentially to the elongated tubular portion. The elongated tubular portion mounts to the outlet tube such that the outlet tube extends through the elongated tubular portion. Alternatively, Incorvia discloses that the adsorbent container can be positioned separately and independently within the refrigerant receiver.
A disadvantage with the Incorvia reference is that it does not disclose details regarding how the adsorbent unit is fused to the filter unit. Another disadvantage is that fusing the adsorbent unit to an elongated tubular portion of the filter unit is likely an unnecessarily complex method of connection. Finally, the disclosure of Incorvia that the adsorbent unit need not be secured within the receiver-dryer, but rather may be freely located therein, is contrary to the goal of integrating and thus simplifying the design and reducing the manufacturing costs of receiver-dryers.
From the above, it can be appreciated that receiver-dryers of the prior art are not yet fully optimized to improve the design and reduce the manufacturing costs thereof. Therefore, what is needed is an improved receiver-dryer that incorporates simple design features and methods of integrating a filter and adsorbent unit for a receiver-dryer at a low cost.
According to the preferred embodiment of the present invention, there is provided an integrated filter and adsorbent unit for use in an integrated receiver-dryer of the present invention. The integrated filter and adsorbent unit includes a filter puck, an adsorbent unit mounted to the filter puck, and an integral feature on the filter puck for integrally fastening the adsorbent unit to the filter puck. The filter puck is adapted for use with the adsorbent unit and preferably includes a disc-shaped body portion, and at least one projection extending therefrom for cooperation with a portion of the adsorbent unit. Likewise, the adsorbent unit is adapted for use with the filter and preferably includes a desiccant bag and a flap extending from the desiccant bag. The flap has a mounting aperture extending therethrough and also has a fastening hole extending therethrough.
In another aspect of the present invention a pressure vessel is adapted for use with a refrigeration system. The pressure vessel includes a housing, an outlet tube extending through the housing for directing a flow of refrigerant out of the housing, and an integrated filter and adsorbent unit that is mounted to the outlet tube. The integrated filter and adsorbent unit includes an adsorbent unit having a flap with a mounting aperture therethrough such that the outlet tube extends through the mounting aperture. A filter body likewise includes an aperture therethrough, wherein the outlet tube extends through the aperture. The filter body further includes a projection extending therefrom that has a displaced portion for retaining the flap of the adsorbent unit between the displaced portion and the filter body.
In a final aspect of the present invention, there is provided a method of manufacturing the integrated filter and adsorbent unit for use with a pressure vessel of a refrigeration system. The method includes the following steps. Manufacturing a filter body having a projection extending therefrom, producing an adsorbent unit having a flap extending therefrom, and assembling the adsorbent unit to the filter body by mounting the adsorbent unit to the filter body and then upsetting the projection over a portion of the flap to form a displaced portion of the projection for retaining the flap between the displaced portion and the filter body.
It is an object of the present invention to provide an improved integrated receiver-dryer for use in an air-conditioning system and to provide a related manufacturing method.
It is another object that an improved adsorbent unit and filter body subassembly is provided.
It is still another object that an integrated filter body and adsorbent unit is provided, such that separate fasteners or complicated fastening arrangements are avoided.
It is yet another object to provide an integrated filter body and adsorbent unit that is easily and inexpensively assembled and installed into a pressure vessel.
It is a further object of the present invention to use the integrated adsorbent unit and filter body to simplify the design and assembly of refrigerant pressure vessel assemblies to reduce manufacturing costs.
These objects and other features, aspects, and advantages of this invention will be more apparent after a reading of the following detailed description, appended claims, and accompanying drawings.